Homolysis, or homolytic cleavage, is a way of breaking a bond in which each of the two fragments keeps one of the two shared electrons, generating two radicals. The prefix 'homo-' signals that the electrons are split evenly. It matters because it is the bond-breaking step that creates the radicals needed for chain reactions. Homolysis contrasts with heterolysis, in which one fragment takes both electrons to give an anion and a cation.

均裂(均裂断键)是一种断键方式,其中两个碎片各保留两个共享电子中的一个,生成两个自由基。前缀“homo-(均)”表示电子被均匀地分开。它之所以重要,是因为它是产生链式反应所需自由基的断键步骤。均裂与异裂形成对照,后者由一个碎片获得全部电子,生成一个阴离子和一个阳离子。